Management and Conservation

Foraging Preferences of Canada Geese Among

Turfgrasses: Implications for Reducing

Human–Goose Conflicts

BRIAN E. WASHBURN,1 United States Department of Agriculture, Wildlife Services, National Wildlife Research Center, Ohio Field Station,

6100 Columbus Avenue, Sandusky, OH 44870, USA

THOMAS W. SEAMANS, United States Department of Agriculture, Wildlife Services, National Wildlife Research Center, Ohio Field Station,

6100 Columbus Avenue, Sandusky, OH 44870, USA

ABSTRACT Canada geese (Branta canadensis) can cause serious damage to turfgrass areas and create human

health and safety concerns (e.g., collisions with aircraft, disease transmission). We conducted a study during

2005–2007 to determine if Canada geese exhibit a feeding preference among various commercially available

turfgrasses. Behavioral responses of captive geese to 9 turfgrasses, bare ground, and litter were observed over 6

4-week trials during July–September following the installation of selected turfgrasses into experimental

arenas. Captive geese preferred to forage on Kentucky bluegrass, creeping bentgrass, and fine fescue sods

compared to centipedegrass, St. Augustinegrass, and zoysiagrass. Forage qualities and macronutrient levels

varied among the turfgrasses and might explain the foraging preferences geese exhibited during this study.

Canada goose feeding rate was positively correlated with crude protein, nitrogen content, and calcium, but

negatively correlated with acid detergent fiber content, within various turfgrasses. Our findings suggest

careful selection of turfgrasses could be an effective method for reducing Canada goose conflicts in urban and

suburban areas.  2011 The Wildlife Society.

KEY WORDS Branta, feeding, geese, landscape management, nutrition, turfgrasses, urban.

Human–wildlife conflicts occur throughout the world and

involve a wide variety of wildlife species and a diversity of

problems, including damage to agricultural crop and forest

resources, impacts to livestock production, issues related to

invasive and exotic species, and wildlife–human disease

transmission (Bruggers et al. 2002, Conover 2002,

Messmer 2009). Conflicts between humans and wildlife

frequently occur in suburban and urban areas, where high

densities of humans and wildlife species adapted to living in

close proximity to humans co-exist (Adams et al. 2005).

Resident (i.e., non-migratory) Canada geese (Branta canadensis) can be a significant problem within urban and suburban environments. In addition to causing direct damage to

vegetation (via trampling and removal), geese grazing on

turfgrasses and plants in manicured industrial lawns, parks

and recreational areas, on sports fields, on golf courses, and

around private homes can adversely affect humans and their

use of such areas by littering these areas with feces (Conover

and Chasko 1985, Conover 1991). Urban geese directly

affect human health and safety by posing a risk to safe aircraft

operations (Dolbeer et al. 2000, Dolbeer 2009), contaminating water resources (Conover and Chasko 1985, Manny et al.

1994), behaving aggressively during the nesting season

(Smith et al. 1999), and potentially transmitting diseases

to humans (Feare et al. 1999, Kullas et al. 2002, Olsen

et al. 2006).

Integrated wildlife damage management programs that use

a variety of tools and techniques are most effective for

reducing human–wildlife conflicts (Fall and Jackson

2002). Management efforts to address resident Canada goose

conflicts often involve the use of hazing and scare devices

(Smith et al. 1999, York et al. 2000, Holevinksi et al. 2007),

habitat modification (Cooper 1998), translocation of individuals (Cooper and Keefe 1997), or lethal removal of geese

(Cooper and Keefe 1997, Smith et al. 1999). One component

of a management program to reduce human–goose conflicts

could be to reduce the attractiveness of turfgrass areas to

Canada geese by installing plant species and cultivars (cv.)

that are not favored by foraging geese. However, this aspect

must be balanced with the aesthetic and recreational values of

turfgrass areas for humans (Ulrich 1986, Casler 2006) and

the availability, ease of establishment, and maintenance ability of selected turfgrass species and cultivars (Casler and

Duncan 2003, Casler 2006).

Knowledge of Canada goose foraging behavior and feeding

preferences, especially related to commercially available turfgrasses that are commonly used in urban and suburban

situations, could be useful in alleviating human–goose conflicts (Cooper 1998, Conover 1991, Washburn et al. 2007).

The objectives of our study were to: 1) determine if Canada

geese exhibit a foraging preference when given a choice

among various commercially available turfgrass types used

Received: 29 November 2010; Accepted: 7 August 2011;

Published: 7 December 2011

1

E-mail: brian.e.washburn@aphis.usda.gov

The Journal of Wildlife Management 76(3):600–607; 2012; DOI: 10.1002/jwmg.293

600 The Journal of Wildlife Management  76(3)
in the United States, 2) quantify forage qualities and nutritional content of these turfgrasses, and 3) identify turfgrass

characteristics that might influence foraging preferences by

Canada geese.

STUDY AREA

We conducted this study from June through October 2005–

2007 at the National Aeronautics and Space Administration’s

Plum Brook Station, Erie County, Ohio (418370 N, 828660

W). Existing goose housing facilities (associated with a

fenced 2-ha pond) adjacent to grasslands allowed for experiments on behavioral response of captive birds to different

vegetation types without the disturbances characteristic of

urban feeding sites (e.g., golf courses).

METHODS

Study Animals

We captured wild adult Canada geese of undetermined sex in

northern Ohio during the molt period (i.e., June) of 2005–

2007 and transported them to our goose holding facilities

where they were provided whole-kernel corn, poultry pellets,

grass, and water ad libitum. We trimmed the primary feathers from the right wing of each bird prior to releasing them

into the holding facility so that the birds would remain

flightless during experiments.

Prior to each experiment, we randomly selected 24 experimentally naive geese and herded them into a 0.4-ha holding

pen that was adjacent to the main holding facility. Wholekernel corn, poultry pellets, shade, grass, and a 20-m2 area of

the pond were available to geese in the holding pen. Each

goose was randomly assigned to 1 of 6 arenas (i.e., 4 geese per

arena). We placed an arena-specific color-coded neck band

on each goose to ensure the same geese were placed into the

same arena throughout an experiment.

Experimental Design

Each year of the study, we established 5 experimental and 1

control arenas (12.2 m 15.2 m). Each arena was divided

into 4 6.1-m 7.6-m plots. We assigned 1 of 4 turfgrasses

to each plot within an arena prior to arena construction. We

obtained and installed turfgrass sods into the appropriate plot

within each arena during June of each year. During 2005

(experiments 1 and 2), the 4 turfgrasses studied included

Kentucky bluegrass (Poa pratensis L.; equal mixture of

Nudestiny, Award, Rugby II, and Absolute cv.), tall fescue

(Schedonorus phoenix (Scop.) Holub) [an equal mixture of an

endophyte-free cv. (Arid III) and a high-endophyte cv.

(Pixie)], common bermudagrass (Cynodon dactylon L.) cv.

Quickstand, and zoysiagrass (Zoysia japonica Steudel) cv.

Zenith. During 2006 (experiments 3 and 4), only 3 turfgrass

sods [creeping bentgrass (Agrostis stolonifera L.) cv.

Penncross, buffalograss (Buchloe dactyloides (Nutt.)

Engelm) cv. Legacy, and zoysiagrass cv. Zenith] could be

delivered in time for establishment. The fourth plot within

each of the 6 arenas was treated as bare ground (i.e., no sod

and vegetation killed with glyphosate [Round-up PROTM,

Monstanto Inc., St. Louis, MO]). Following the end of

experiment 3, we killed all 5 creeping bentgrass plots using

glyphosate on 21 August 2006 because of significant mortality and declines in the quality of the bentgrass turf. Thus,

litter (i.e., dead grass) replaced creeping bentgrass as a treatment during experiment 4. During 2007 (experiments 5 and

6), the 4 turfgrasses included fine fescue (mixture comprised

of 40% hard fescue [Festuca trachyphylla (Hackel) Krajina] cv.

Nordic, 40% creeping red fescue [F. rubra ssp. rubra Gaudin]

Audubon, and 20% chewings fescue [F. rubra ssp. commutate

(Thuill.) Nyman] cv. Jamestown IV), centipedegrass

(Eremochloa ophiuroides (Munro) Hack.) cv. Common, St.

Augustinegrass (Stenotaphrum secundatum (Walt.) Kuntze)

cv. Palmetto, and zoysiagrass cv. Zenith. Kentucky bluegrass

sod was placed in all 4 plots within the control arena in 2005

(experiments 1 and 2), zoysiagrass sod was placed in 3 of the

4 plots within the control arena in 2006 (experiments 3 and

4), and zoysiagrass sod was placed in all 4 plots within the

control arena in 2007 (experiments 5 and 6).

Following installation and establishment of the turfgrass

sod, we erected a 1.5-m tall black plastic fence around the 6

arenas to keep the geese within their respective arenas. We

mowed all plots within the arenas to a height of 15–20 cm

prior to the start of the first experiment each year so that all

turfgrasses were initially of similar height.

Goose Behavioral Observations

Each day of an experiment, we placed 2 0.5-m diameter pans

of water centrally within each arena. We herded 4 geese into

each arena daily by 0830 hours and allowed them to graze on

the turfgrasses until 1200 hours, when we returned them to

their holding pen. Three observers stationed on 4.9-m tall

towers 20 m from the arenas monitored goose activity. We

observed geese for 2 1-hour periods (0.5 and 2.5 hr after we

herded geese into arenas) 3 days per week for 4 weeks. Each

observer watched 2 arenas, alternating between arenas every

minute. At the start of each minute, observers recorded the

initial number of geese in each turfgrass plot, then for the

following 0.5 minute counted the number of bill contacts

(total for all 4 geese) with each turfgrass plot in the arena

(Washburn et al. 2007). We conducted behavioral observations of the geese for 12 days during 27 July–19 August 2005

(experiment 1), 24 July–18 August 2006 (experiment 3), and

6 July–1 August 2007 (experiment 5).

Following the end of the first experiment each year, the

turfgrasses were not grazed by geese for at least 10 days. We

mowed all turfgrass plots to a height of 15–20 cm prior to the

start of the second experiment. We selected a new set of 24

experimentally naive geese, placed them into the holding

pen, and fitted them with color-coded neck bands. We

conducted behavioral observations of geese during the second 4-week experiment each year for 12 days during 29

August–22 September 2005 (experiment 2), 11 September–

6 October 2006 (experiment 4), and 10 August–5 September

2007 (experiment 6).

Turfgrass Forage Quality

We collected fresh samples of the 9 turfgrasses between

experiments. We collected 6 replicate samples of each turfgrass from randomly selected arenas by cutting the grass

Washburn and Seamans  Goose Foraging Preferences 601
swards with electric clippers. We removed dead plant material by hand to ensure samples contained only living plant

material. We immediately placed 3 samples of each turfgrass

into plastic bags and froze the samples at 208 C within

15 minutes of collection. We placed the remaining 3 samples

of each turfgrass in a drying oven within 30 minutes of

collection and dried them for 48 hours at 508 C. We stored

dried turfgrass samples individually in paper bags.

We transported frozen turfgrass samples to the Holmes

Laboratory, Inc. (Millersburg, OH) for forage and feed

analyses. They used standard laboratory methods

(Association of Official Analytical Chemists 2007) to determine forage qualities (moisture content, crude fat, crude

protein, water-soluble carbohydrates [WSC], acid detergent

fiber [ADF], neutral detergent fiber [NDF], lignin, and ash)

from each of the 9 turfgrasses. Acid detergent fiber (i.e.,

cellulose þ lignin) has been shown to be a reliable estimator

of digestibility of foods in Anatidae (Prop and Deerenberg

1991, Durant et al. 2003). Neutral detergent fiber (i.e.,

ADF þ hemicelluose) is inversely related to forage intake,

thus as NDF increases total intake decreases (Pond et al.

1995).

We sent dried turfgrass samples to the Pennsylvania State

University Agricultural Analytical Services Laboratory

(University Park, PA) for nutrient and silica content analyses. They used standard laboratory methods for plant tissue

analysis (Miller 1998) to determine macronutrient levels

(nitrogen, phosphorus, potassium, calcium, magnesium,

and sodium) and total silicon in each of the 9 turfgrasses.

In grasses, silica uptake is a plant defense against herbivory

(Vicari and Bazely 1993) and thus might influence foraging

rates by geese.

Statistical Analyses

We analyzed Canada goose behavioral and feeding rate data

from each of the 6 foraging experiments independently.

Goose behavioral and foraging data collected during successive observations are likely not independent. Therefore, we

computed a daily average of the number of geese per plot and

bill contacts per minute for all 4 geese combined (hereafter

BCPM) for each turfgrass type (i.e., plot) within each arena.

We compared the average number of geese observed and the

BCPM in each turfgrass type using repeated measures analysis of variance with turfgrass type as a fixed effect, the 5

arenas as replications, and the 12 days as repeated measures

(Crowder and Hand 1990). When the main effect (turfgrass

type) was found to be significant, we conducted means

comparisons using Fisher’s protected Least Significant

Difference (LSD) tests (Zar 1996). We considered differences significant at P  0.05 and conducted all statistical

analyses using SAS 9.1 (SAS Institute, Inc., Cary, NC).

Additionally, we used linear regression analysis (Zar 1996)

to determine if trends in goose foraging rate occurred within

individual turfgrass types during each experiment.

We compared forage quality characteristics (moisture,

crude fat, crude protein, WSC, ADF, NDF, lignin, and

ash), macronutrient levels (nitrogen, phosphorus, potassium,

calcium, magnesium, and sodium), and total silica content

among the 9 turfgrasses using Kruskal–Wallis tests and

considered differences significant at P  0.05 (Zar 1996).

We identified potential relationships between observed

goose foraging and the forage quality and nutritional characteristics of the turfgrasses. We calculated Pearson’s correlation coefficient for goose foraging rate (BCPM; averaged

across experiments) with each forage quality characteristic

(moisture, crude fat, crude protein, WSC, ADF, NDF,

lignin, and ash), macronutrient level (nitrogen, phosphorus,

potassium, calcium, magnesium, and sodium), and total silica

content for each of the 9 turfgrasses and considered correlations to be significant at P  0.05 (Zar 1996).

RESULTS

Goose Behavioral and Foraging Observations

During experiment 1, the numbers of geese observed did not

differ (F3,16 1⁄4 1.86, P 1⁄4 0.18) and the BCPM was not

statistically different (F3,16 1⁄4 2.87, P 1⁄4 0.07) among the

4 turfgrasses (Table 1). However, the BCPM by geese in

bluegrass, tall fescue, and bermudagrass plots was more than

22 times greater than BCPM by geese in zoysiagrass plots

(Fig. 1A). We believe this difference is biologically significant and represents an important difference in feeding rate.

Canada geese foraged in the Kentucky bluegrass control

Table 1. Mean number of Canada geese per plot and mean number of bill

contacts per minute (for 4 geese combined) during 6 experiments with

commercially available turfgrasses. Data are presented as mean  1 SE.

Turfgrass

No. of geese

per plota

Bill contacts

per minutea

Experiment 1

Kentucky bluegrass 0.8  0.1 A 22.3  6.6 A

Tall fescue 1.2  0.5 A 22.4  10.2 A

Common bermudagrass 1.2  0.3 A 28.4  7.5 A

Zoysiagrass 0.4  0.1 A 0.8  0.2 A

Experiment 2

Kentucky bluegrass 1.7  0.2 A 81.7  11.2 A

Tall fescue 0.6  0.2 B 5.3  1.4 C

Common bermudagrass 1.0  0.2 AB 19.3  3.4 B

Zoysiagrass 0.4  0.2 B 1.9  0.6 C

Experiment 3

Creeping bentgrass 1.2  0.2 A 41.9  5.0 A

Buffalograss 0.7  0.2 A 18.8  5.4 AB

Zoysiagrass 0.6  0.2 A 6.0  2.3 B

Bare ground (no grass) 1.1  0.3 A 1.3  0.4 B

Experiment 4

Litter (dead grass) 0.7  0.3 A 0.5  0.2 A

Buffalograss 1.8  0.3 B 36.5  3.6 B

Zoysiagrass 0.6  0.3 A 6.2  2.5 A

Bare ground (no grass) 0.7  0.1 A 1.1  0.3 A

Experiment 5

Fine fescue 2.0  0.4 A 19.0  3.4 A

Centipedegrass 0.8  0.2 B 4.1  1.0 B

St. Augustinegrass 0.5  0.2 B 5.6  1.6 B

Zoysiagrass 0.4  0.1 B 3.6  0.9 B

Experiment 6

Fine fescue 1.8  0.2 A 32.0  5.3 A

Centipedegrass 0.7  0.3 B 6.3  2.4 B

St. Augustinegrass 0.5  0.2 B 2.7  0.9 B

Zoysiagrass 0.4  0.1 B 3.0  1.1 B

a Within each experiment, means within the same column with the same

letter are not different (P > 0.05).

602 The Journal of Wildlife Management  76(3)
arena plots (10.6 BCPM) at rates consistent with foraging in

bluegrass sod within the other 5 arenas. Overall, captive

Canada geese spent similar amounts of time in all 4 types

of turfgrass but foraged almost exclusively on the Kentucky

bluegrass, tall fescue, and common bermudagrass sod

(Fig. 1A).

During experiment 2, the numbers of geese observed in

Kentucky bluegrass were greater (F3,16 1⁄4 10.61, P  0.001)

than in tall fescue and zoysiagrass plots, whereas the numbers

of geese in common bermudagrass plots were similar to the

other 3 turfgrasses (Table 1). The BCPM by geese in bluegrass was 4–43 times greater (F3,16 1⁄4 39.79, P  0.001)

than in tall fescue, bermudagrass, and zoysiagrass plots

(Table 1). Canada geese foraged in the Kentucky bluegrass

control arena plots (18.0 BCPM) at a rate less than in the

other 5 arenas. Overall, captive Canada geese preferred to

loaf, preen, rest, and forage in Kentucky bluegrass plots

compared to tall fescue and zoysiagrass plots (Fig. 1B).

During experiment 3, the numbers of geese observed was

similar (F3,16 1⁄4 2.38, P 1⁄4 0.11) among the 3 turfgrass and

bare ground plots (Table 1). The number of bill contacts by

geese in creeping bentgrass plots was 7–32 times greater

(F3,16 1⁄4 21.79, P < 0.001) than the number of bill contacts

by geese in zoysiagrass or bare ground plots; the number of

bill contacts by geese in buffalograss was intermediate

(Table 1). Canada goose foraging on creeping bentgrass

decreased (linear regression: y 1⁄4 3.6211x þ 65.402,

R2 1⁄4 0.36, F1,11 1⁄4 5.67, P 1⁄4 0.04), while foraging on buffalograss increased (linear regression: y 1⁄4 3.3213x  2.838,

R2 1⁄4 0.83, F1,11 1⁄4 47.27, P < 0.001) from the beginning

to the end of experiment 3 (Fig. 2A). Canada geese in the

control arena plots foraged in the zoysiagrass (12.3 BCPM)

and bare ground (2.7 BCPM) plots similarly to the other 5

arenas. Overall, geese spent similar amounts of time in all 3

turfgrass and bare ground plots but foraged almost exclusively in the creeping bentgrass and buffalograss plots

(Fig. 2A).

During experiment 4, more (F3,16 1⁄4 4.46, P 1⁄4 0.02) geese

were observed in buffalograss than in zoysiagrass, bare

ground, and litter plots (Table 1). The number of bill contacts by geese in buffalograss was 6–73 times greater

(F3,16 1⁄4 60.68, P < 0.001) than the number of bill contacts

by geese in zoysiagrass, bare ground, and litter plots. Canada

goose foraging on buffalograss decreased (linear regression:

y 1⁄4 –3.6211x þ 65.402; R2 1⁄4 0.79, F1,11 1⁄4 37.08,

P < 0.001) from the beginning to the end of experiment

3 (Fig. 2B). Canada geese foraged in the zoysiagrass (10.2

BCPM) and bare ground (1.0 BCPM) control plots at rates

consistent with foraging within the other 5 arenas. Overall,

captive Canada geese preferred to loaf, preen, rest, and forage

in buffalograss plots compared to zoysiagrass, bare ground,

and litter plots (Fig. 2B).

During experiments 5 and 6, the numbers of geese observed

in fine fescue were greater (experiment 5: F3,16 1⁄4 8.29,

P 1⁄4 0.002; experiment 6: F3,16 1⁄4 9.59, P  0.001) than

in centipedegrass, St. Augustinegrass, and zoysiagrass plots

(Table 1). The number of bill contacts by geese in fine fescue

was 3–5 times greater (F3,16 1⁄4 13.81, P  0.001) and 5–12

times greater (F3,16 1⁄4 22.58, P  0.001) than the number of

bill contacts by geese in centipedegrass, St. Augustinegrass,

and zoysiagrass plots during experiments 5 and 6, respectively. Canada geese in the control plot arena foraged in the

Figure 1. Mean number of bill contacts per minute by captive Canada geese

in 5 arenas of 4 turfgrass plots during (A) experiment 1, 27 July–19 August

2005 and (B) experiment 2, 29 August–22 September 2005.

Figure 2. Mean number of bill contacts per minute by captive Canada geese

in 5 arenas of 4 turfgrass plots during (A) experiment 3, 24 July–18 August

2006 and (B) experiment 4, 11 September–6 October 2006.

Washburn and Seamans  Goose Foraging Preferences 603
zoysiagrass control plots (experiment 5: 7.3 BCPM; experiment 6: 11.5 BCPM) at rates consistent with foraging in the

zoysiagrass plots within the other 5 arenas. Overall, captive

Canada geese preferred to loaf, preen, rest, and forage in fine

fescue plots compared to centipedegrass, St. Augustinegrass,

and zoysiagrass (Fig. 3A,B).

Turfgrass Forage Quality

Forage quality characteristics (Table 2) varied among the 9

turfgrasses (all H8 > 18.2, P < 0.03). Buffalograss had the

lowest moisture content, whereas creeping bentgrass had the

highest (Table 2). Fine fescue and centipedegrass had greater

crude fat than tall fescue (Table 2). Kentucky bluegrass and

creeping bentgrass had greater levels of crude protein than

common bermudagrass and zoysiagrass (Table 2). Acid

detergent fiber was lowest in Kentucky bluegrass and creeping bentgrass and highest in buffalograss and zoysiagrass

(Table 2). Tall fescue had less NDF and more WSC than

zoysiagrass (Table 2).

Macronutrient levels (Table 3) varied among the 9 turfgrasses (all H8 > 24.0, P < 0.003). Kentucky bluegrass and

creeping bentgrass had greater nitrogen content than common bermudagrass and zoysiagrass (Table 3). Calcium levels

were highest in common bermudagrass and lowest in St.

Augustinegrass and zoysiagrass (Table 3). St. Augustinegrass

had sodium levels that were 5–72 times greater than the

other 8 turfgrasses studied (Table 3). Buffalograss had greater total silica content than fine fescue and creeping bentgrass

(Table 3).

Relationships Between Turfgrass Forage Quality and

Goose Foraging

Goose foraging rate (i.e., BCPM) and forage quality characteristics of turfgrasses were positively correlated for crude

protein (r 1⁄4 0.70, P 1⁄4 0.03, n 1⁄4 9 grasses) and negatively

correlated for ADF (r 1⁄4 0.71, P 1⁄4 0.03, n 1⁄4 9), whereas

correlations between goose foraging rate and turfgrass forage

qualities were absent (all P > 0.05) for moisture, ash, crude

fiber, WSC, NDF, and lignin. Goose foraging rate and

macronutrient levels in the turfgrasses were positively correlated for nitrogen (r 1⁄4 0.73, P 1⁄4 0.03, n 1⁄4 9) and calcium

(r 1⁄4 0.75, P 1⁄4 0.02, n 1⁄4 9), whereas correlations between

goose foraging rate and turfgrass forage qualities were absent

(all P > 0.05) for the other macronutrients measured (phosphorus, potassium, magnesium, sodium) and total silica

content.

DISCUSSION

Our findings clearly demonstrate that Canada geese were

making choices and exhibiting preferences when foraging

among the turfgrass plots. The forage selection patterns of

Canada geese for Kentucky bluegrass in this study are consistent with the findings of other research (Conover 1991,

Pochop et al. 1999). Conover (1991) found that Canada

geese readily foraged on colonial bentgrass (Agrostis castellana

Boiss. & Reuter cv. Highland), a cool-season grass very

Figure 3. Mean number of bill contacts per minute by captive Canada geese

in 5 arenas of 4 turfgrass plots during (A) experiment 5, 6 July–1 August 2007

and (B) experiment 6, 10 August–5 September 2007.

Table 2. Forage qualities of Kentucky bluegrass (KYB), common bermudagrass (BERM), tall fescue (TTF), zoysiagrass (ZOY), creeping bentgrass (BENT),

buffalograss (BUFF), fine fescue (FF), centipedegrass (CENT), and St. Augustinegrass (ST. AUG). Data are presented as mean  1 SE.

Turfgrass

Moisture

(%)

Ash

(%)

Crude fat

(%AFDWa

)

Crude protein

(%AFDW)

WSCb

(%AFDW)

ADFc

(%AFDW)

NDFd

(%AFDW)

Lignin

(%AFDW)

KYB 69.9  1.7 8.5  0.3 2.7  0.1 22.8  0.5 20.0  1.0 24.5  1.2 55.5  1.0 0.5  0.2

BERM 57.0  3.9 6.6  0.1 1.6  0.2 11.4  0.5 8.7  3.7 31.2  0.2 76.1  3.0 3.9  0.3

TTF 72.6  1.5 11.9  0.1 1.4  0.1 15.3  0.8 24.9  0.9 29.4  0.5 52.0  0.7 0.9  0.1

ZOY 62.8  2.1 7.7  0.2 1.6  0.1 11.8  0.7 3.3  1.3 33.3  0.4 80.9  1.3 2.1  0.2

BENT 85.2  1.3 14.6  1.3 2.6  0.1 31.2  0.5 16.3  2.9 23.2  0.4 62.2  9.9 1.2  0.4

BUFF 45.3  0.9 8.6  0.1 1.6  0.1 14.4  0.5 10.7  3.0 32.8  0.4 72.3  3.0 2.7  0.1

FF 72.4  2.1 8.7  0.1 3.2  0.1 20.2  0.3 11.9  5.9 28.6  0.5 67.4  8.1 0.6  0.1

CENT 75.2  1.0 8.9  0.2 3.4  0.4 13.7  0.8 12.7  3.6 31.0  1.2 68.8  3.1 1.3  0.3

ST. AUG 76.6  1.5 9.7  0.2 2.0  0.1 17.1  0.6 16.3  1.0 28.6  0.3 63.6  0.2 0.7  0.1

a %AFDW 1⁄4 Percent ash-free dry weight. b WSC 1⁄4 water-soluble carbohydrates. c ADF 1⁄4 acid detergent fiber. d NDF 1⁄4 neutral detergent fiber.

604 The Journal of Wildlife Management  76(3)
closely related to creeping bentgrass. In addition to foraging,

time in each plot might be spent loafing or in other nonfeeding behaviors (Belant et al. 1997). Although geese also

spent time in the zoysiagrass plots, they showed little preference for this turfgrass when foraging.

Overall, the rate of Canada goose foraging upon the various

turfgrasses was consistent during the experiments, with 2

interesting exceptions. During experiment 3, the creeping

bentgrass sod exhibited a visible reduction in turfgrass quality

(it appeared to be dying from an unknown disease) which

reduced the quantity and likely the forage quality of available

bentgrass in the plots. Although Canada goose foraging rates

decreased as the experiment progressed, they continued to

forage on this sod at a high rate in all 5 arenas. This suggests

that the creeping bentgrass provided a favorable forage

(compared to other turfgrasses) to the geese. Canada goose

foraging on buffalograss increased during experiment 3 and

then steadily decreased during experiment 4. As buffalograss

is a warm-season grass, we suspect the responses in feeding

rate by geese followed the forage value of buffalograss during

its annual cycle.

The nutritional content of most turfgrass species and cv. are

unknown, primarily because these grass species or specific

turf-type cv. are not used as for forage in animal production

agriculture (Ball et al. 1991). Geese, because of their high

daily energy requirements and simple gastrointestinal tract

with a limited ability to digest fiber (Buchsbaum et al. 1986,

Sedinger et al. 1989, Sedinger 1997), need to ingest large

quantities of forage with high concentrations of digestible

nutrients to meet their nutritional needs (Ydenberg and

Prins 1981, Durant et al. 2004). Therefore, grazing

Anatidae (including various species of geese) apparently

make foraging choices based on the nutritional content

and chemical composition of plants (Owen 1975,

Gauthier and Bedard 1991, McKay et al. 2001). Geese prefer

to forage on plants that are high in water and protein content

(Owen 1973, Owen et al. 1977, Sedinger and Raveling 1984,

McKay et al. 2001). Digestible crude protein intake is an

important component in the foraging decisions of geese

(Sedinger 1997, Durant et al. 2004). Protein concentration

within forage plants has been shown to influence forage

selection in a variety of goose species, including barnacle

geese (Branta leucopsis; Prins and Ydenberg 1985), darkbellied brent geese (B. bernicla bernicla; McKay et al.

2001), white-fronted geese (Anser albifrons albifrons; Owen

1976), graylag geese (A. anser; Van Liere et al. 2009), and

gosling Canada geese (Sedinger and Raveling 1984). In this

study, adult Canada geese foraged most on and therefore

seemed to select turfgrasses (i.e., Kentucky bluegrass, creeping bentgrass, and fine fescue) that exceeded 20% protein (or

nitrogen) content.

In addition to protein levels, ADF might influence forage

selection by geese. The turfgrasses fed upon most often by

Canada geese in this study (i.e., Kentucky bluegrass and

creeping bentgrass) had low levels of ADF whereas turfgrasses that were less fed upon (i.e., centipedegrass and

zoysiagrass) contained high levels of ADF. Gauthier and

Hughes (1995) found that high fiber content appeared to

reduce greater snow goose (Chen caerulescens atlantica) foraging on willow (Salix spp.) leaves. Also, Prop et al. (2005)

found that ADF had a negative effect on the digestibility of

organic matter by barnacle geese.

With the exception of calcium, our findings suggest macronutrient (e.g., mineral) content of turfgrasses does not

appear to affect foraging choice by geese. Similarly,

Mathers and Montgomery (1997) found forage choice in

free-ranging pale-bellied brent geese (B. bernicla hrota) was

related to forage quality (e.g., low fiber content) rather than

mineral content of consumed forage plants. Prins and

Ydenberg (1985) found protein levels, but not minerals,

influenced diet choice in wintering barnacle geese.

However, lesser snow geese (C. caerulescens caerulescens) selected plants based on the nutrient content in order to obtain

necessary minerals (nitrogen, calcium and phosphorous) to

promote growth while on their breeding grounds (Gadallah

and Jefferies 1995). Consequently, mineral content of plants

might influence goose forage selection during certain periods

of the year when energetic demands for those minerals are

high (e.g., egg production).

Secondary plant defense compounds, such as alkaloids and

tannins, cause geese to limit intake of or avoid feeding on

certain plants (Buchsbaum et al. 1984, Conover 1991,

Gauthier and Hughes 1995). The tall fescue endophyte

(Neotyphodium coenophialum) is a naturally occurring fungus

that forms a symbiotic relationship with the grass (Ball et al.

1991). Secondary plant defense compounds (e.g., alkaloids)

produced by endophyte-infected tall fescue act as a feeding

deterrent (e.g., taste aversion) by causing post-ingestion

distress in animals that consume the plant (Aldrich et al.

1993, Schmidt and Osborn 1993, Bacon and Hill 1997).

Table 3. Macronutrient and total silica (expressed on a dry weight-basis) in Kentucky bluegrass (KYB), common bermudagrass (BERM), tall fescue (TTF),

zoysiagrass (ZOY), creeping bentgrass (BENT), buffalograss (BUFF), fine fescue (FF), centipedegrass (CENT), and St. Augustinegrass (ST. AUG). Data are

presented as mean  1 SE.

Turfgrass Nitrogen (%) Phosphorus (%) Potassium (%) Calcium (%) Magnesium (%) Sodium (%) Silicon (mg/kg)

KYB 3.61  0.07 0.31  0.02 2.33  0.06 0.43  0.03 0.19  0.02 0.04  1.20 11,199  394

BERM 1.76  0.06 0.24  0.01 1.13  0.03 0.47  0.09 0.14  0.01 0.08  0.01 12,085  900

TTF 2.05  0.09 0.42  0.01 2.52  0.04 0.22  0.09 0.35  0.01 0.01  0.01 20,388  529

ZOY 1.78  0.07 0.31  0.02 1.54  0.03 0.18  0.02 0.14  0.01 0.01  0.01 14,270  322

BENT 5.29  0.01 0.61  0.01 3.28  0.01 0.67  0.02 0.24  0.01 0.04  0.01 4,826  97

BUFF 2.18  0.06 0.28  0.01 0.92  0.01 0.23  0.05 0.12  0.01 0.01  0.01 22,510  573

FF 3.08  0.04 0.38  0.01 2.55  0.05 0.37  0.01 0.19  0.01 0.01  0.01 8,877  199

CENT 2.06  0.06 0.34  0.01 2.24  0.02 0.28  0.02 0.25  0.01 0.01  0.01 14,032  360

ST. AUG 2.32  0.02 0.46  0.01 2.55  0.02 0.15  0.03 0.25  0.01 0.43  0.04 11,349  753

Washburn and Seamans  Goose Foraging Preferences 605
Many tall fescue cv. have high levels of tall fescue endophyte

infection (Mohr et al. 2002). In this study, we used a

turfgrass sod grown from a mix of endophyte-free and

high-endophyte tall fescue cv. We suspect that the foraging

on tall fescue that occurred (primarily in experiment 1) was a

result either of the geese selectively grazing the endophytefree tall fescue plants within the plots or geese were ingesting

the high-endophyte tall fescue at levels low enough to avoid

the negative effects of alkaloid consumption. Washburn et al.

(2007) found captive Canada geese avoided foraging on

high-endophyte tall fescue turfgrass sod when the percent

of tall fescue within the sward exceeded 90%. Also, Conover

and Messmer (1996) reported captive Canada geese preferred to graze on non-infected tall fescue cv. compared to

endophyte-infected tall fescue cv., and that geese foraging on

endophyte-infected tall fescue suffered negative effects (e.g.,

lost body mass).

In addition to nutrient levels and plant defense chemicals,

physical characteristics of turfgrasses (e.g., leaf tensile

strength, hairy leaves) might influence forage selection by

Canada geese (Lieff et al. 1970, Williams and Forbes 1980,

Conover 1991). Although we did not specifically examine

physical characteristics of turfgrasses in our study, we believe

future research efforts to further understand the influence of

physical and/or nutritional characteristics upon forage selection patterns in Anatidae might consider evaluating physical

characteristics of turfgrasses.

We acknowledge our study was conducted in a captive

setting and that free-ranging Canada geese might exhibit

different foraging preferences among turfgrasses that are

available with a given landscape. We recommend field trials

be conducted in various parts of the United States (and

elsewhere) to determine which turfgrasses and turf-type

cv. might be useful in different physiographic regions of

North America.

MANAGEMENT IMPLICATIONS

The findings from our 3-year study of foraging preferences

by Canada geese suggest selected commercially available

turfgrasses (e.g., zoysiagrass, centipedegrass, and St.

Augustinegrass) might be particularly useful in reseeding

and vegetation renovation projects within areas where

Canada geese are unwanted (e.g., parks, athletic fields, airports, and golf courses). Conversely, creeping bentgrass,

Kentucky bluegrass, and fine fescues should be avoided

when formulating seed mixtures for reseeding areas where

human–goose conflicts might occur. We recommend managers and landscapers use caution when selecting common

bermudagrass and buffalograss for reseeding projects, especially when other less preferred turfgrasses are present in the

general area.

The avoidance or preference for certain turfgrasses by

foraging geese might be due to the nutritional value, the

physical characteristics of these turfgrasses, the presence of

secondary plant defense compounds, or a combination of

factors. Thus, an understanding of how the physical and

nutritional characteristics of commercially available turfgrasses influence forage selection by geese could be useful

for predicting the attractiveness of those plants to Canada

geese and allow for the selection of grasses that might reduce

human–goose conflicts in some situations.

Attractiveness to foraging wildlife (e.g., Canada geese) is

one aspect of turfgrass selection that must be balanced with

the aesthetic and recreational values of turfgrass areas for

humans. In addition, managers and landscapers must consider the availability, ease of establishment, and maintenance

ability of selected turfgrass species and cultivars when selecting turfgrasses for reseeding and revegetation projects.

ACKNOWLEDGMENTS

R. Beason, B. Blackwell, L. Kutschbach-Brohl, D. Helon, S.

Johnston, L. Tyson, T. DeVault, and others provided field

assistance and comments on earlier drafts of the manuscript.

We thank the National Aeronautics and Space Administration

for providing access to the study site. Funding for this study

was provided by the Federal Aviation Administration (FAA).

Opinions expressed in this study do not necessarily reflect

current FAA policy decisions governing the control of wildlife

on or near airports.

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